Exploring, drilling and completing hydrocarbon and other wells are generally complicated, time consuming and ultimately very expensive endeavors. As a result, over the years, well architecture has become more sophisticated where appropriate in order to help enhance access to underground hydrocarbon reserves. For example, as opposed to wells of limited depth, it is not uncommon to find hydrocarbon wells exceeding 30,000 feet in depth. Furthermore, today's hydrocarbon wells often include deviated or horizontal sections aimed at targeting particular underground reserves. Indeed, at targeted formation locations, it is quite common for a host of lateral legs and fractures to stem from the main wellbore of the well toward a hydrocarbon reservoir in the formation.
The above described fractures may be formed by a fracturing operation, often referred to as a stimulation operation. The stimulation or fracturing operation, involves pumping of a fracturing fluid at high pressure into the well in order to form the fractures and stimulate production of the hydrocarbons. The fractures may then serve as channels through the formation through which hydrocarbons may reach the wellbore. The indicated fracturing fluid generally includes a solid particulate referred to as proppant, such as sand. The proppant may act to enhance the formation of fractures during the fracturing operation and may also remain primarily within fractures upon their formation. In fact, the fractures may remain open in part due to their propping open by the proppant.
The above described proppant for the fracturing operation may be supplied from a proppant delivery unit located at the oilfield near the well. This unit is generally very large due to the amount of proppant that may be required for any given fracturing operation. For example, where the proppant is a conventional dry sand, a fully loaded unit may exceed half a million pounds in weight. Once more, as wells become deeper and of ever increasing complex architecture, efforts to provide even larger ready supplies of proppant at the oilfield are increasingly common. That is, more downhole fracturing locations may be involved, thus requiring a greater available supply of proppant.
From an equipment standpoint, greater on-site or near-site supplies of proppant may include the use of mobile silos or even larger stationary silos that are used to gravity feed a blender therebelow. Thus, a proppant slurry may be formed and utilized in short order to support various fracturing operations. As a practical manner, however, this means that potentially several million pounds of proppant may require transport and storage at a given location. Adding to this is the weight and footprint issues for the equipment itself which is necessary to allow for such a ready bulk supply.
In terms of limiting the overall footprint, a variety of systems may be available. For example, systems may be utilized in which smaller silo-like storage containers are transported to the oilfield and then erected to a vertical position. Thus, the footprint of the equipment may be reduced due to the vertical orientation and follow-on gravity feeding, mixing and use of a frac slurry may ensue.
Unfortunately, while this does address footspace issues to a degree, erecting a proppant loaded silo has its practical limitations. For example, erecting more than a few million pounds of a proppant filled silo may be impractical with conventionally available hydraulics. Thus, on larger job sites with more fracturing operations, the need to deliver several such small loaded silos may exist.
As an alternative to delivering small loaded silos, efforts have been undertaken to install larger, more permanent silos that may be empty when installed but subsequently filled with proppant for use at the oilfield. Again, the vertical orientation of such on-site silos helps keep footspace devoted to fracturing equipment to a minimum. Once more, such larger silos may be gravity fed and outfitted with mixing equipment and other features therebelow for ongoing operational use. However, setting up and filling these larger silos with proppant may come with challenges as well.
For example, in order to maximize efficiencies in terms of set up time and filling, unique modular forms of equipment may be employed. More specifically, a mobile compacted silo base frame may be positioned at the oilfield with a truck, unfolded and utilized as the foundation for the erection of a multi-unit silo thereover. Similarly, mobile compacted elevators with extendable auger arms may be positioned at the oilfield with another truck, vertically erected, and later utilized to transfer proppant from delivery trucks to the silo. In this way, a much greater amount of proppant may be made available at the oilfield site in a space saving fashion.
The process of unfolding the silo base frame or extending the auger arms face the unique challenge of re-orienting or articulating several thousand pounds of tension within a compact limited space of operation. That is, unlike erecting an elevator to a vertical position, the space for accommodating large scale hydraulics is unavailable for wings of the silo base frame and/or the auger arms.